This invention relates to a lift truck and more particularly to the mast positioning mechanism for mounting the mast to the lift truck and controlling its position relative thereto.
Fork lift trucks are widely used in many industries for stacking operations wherein material is stacked in vertical tiers. To conserve floor space, the distance between the vertical tiers is minimal and the lift trucks are generally designed with a short wheel base for maneuverability in such cramped quarters. Thus, the load carrying capacity is governed partially by the distance that the forks extend ahead of the front wheels. For this reason, the placement of the forks and the mast relative to the front wheels throughout their working lift height is an important consideration in all lift truck designs.
Several load carrying vehicles have their material handling implement mounted on the forward ends of a pair of lift arms which are pivotally connected to the vehicle body. However, this implement mounting arrangement has not been widely accepted for mounting a mast to a lift truck since the lift arms would swing the mast in an arc such that the forks move forwardly as they are raised, thereby reducing the load carrying capacity.